Macau

Few Massachusetts residents may be familiar with Macau, but the Chinese administrative region that has become the most lucrative gambling market in the world has caught the eye of state regulators as they complete background checks on two casino companies.

Sheldon Adelson, the largest foreign investor in China, has invested tens of millions of dollars in influencing the 2012 election and has vowed to spend $100 million to put his thumb on the scale for Mitt Romney in November.